Circuit board mounting assembly and method

ABSTRACT

An electronic system, such as a computer, having a housing with a door opening into an interior of the housing. An insertion mechanism is mounted on the door and includes a handle provided on an exterior side of the door and a driver portion provided on an interior side. The driver portion includes a rotatable latch driver attached to the handle and a rotatable latch follower engaging the latch driver through a set of gears. A movable mount is slideably mounted onto the door and a circuit board assembly is mounted onto the movable mount. After the door of the housing is closed, rotation of the handle causes rotation of the latch driver, which, in turn, causes rotation of the latch follower. The latch driver and follower engage the movable mount such that their rotation causes forward movement of the movable mount and the circuit board assembly. This forward movement causes an edge connector provided along a forward edge of the circuit board assembly to mate with a connection socket provided in an interior portion of the housing.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation of application Ser. No. 09/470,834, filed on Dec.23, 1999 now U.S. Pat. No. 6,111,754.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a system and method for mounting a printedcircuit board onto a computer assembly.

2. Background

Printed circuit boards are thin plates on which computer chips and otherelectronic components are mounted. In recent years, circuit boards havebeen used extensively in electrical equipment. For example, computersare routinely constructed of a plurality of printed circuit boards, eachcontaining a portion of the electronics required to allow the computerto operate.

A typical circuit board includes an edge connector provided along aleading or forward edge of the board. This edge connector includeselectrical contacts which allow the circuit board to communicate withthe rest of the computer system. These edge connectors are received inconnection sockets located on another circuit board. The amount of forcerequired to seat a circuit board into a connection socket is dependenton the number of contacts and type of electrical connectors used. For agiven type of connector, the more contacts that must be mated typicallyincreases the force that must be used to seat the circuit board. In anexemplary circuit board, the three edge connectors require a 100 poundinsertion force. Insertion mechanisms have been used to apply anaccurate and sufficiently powerful insertion force to an edge of thecircuit board opposite the edge connectors. These types of mechanismsare located coplanar to the circuit board, and thus occupy space withinthe computer housing adjacent to the board edge, which may interferewith access to the internal components.

The computer housings used for state-of-the-art computer systems areoften densely filled with multiple circuit boards, media drives, powersupplies, cables, and other computer components. Such dense packingsignificantly increases the difficulty with which these components canbe accessed for upgrading and repair. The case of the Power Mac G4 byApple Computer, Inc. has a swing-open side door that allows easy accessto the internal components. In the Power Mac G4, the motherboard andother key components are mounted onto the door, leaving the powersupply, media drives, and other non-circuit board components inside thecomputer housing.

The use of ribbon cables to connect components results in increased costand decreased performance, as compared to systems using edge connectors;circuit board edge connectors provide higher speed signals and bettersignal integrity. However, the Power Mac's design uses ribbon cables toenable the door mounting of the circuit board. The ribbon cables areneeded to provide a connection between the motherboard and the othersystem components that can flex to accommodate the opening and closingof the door.

SUMMARY

In accordance with an aspect of the present invention, an electronicsystem, such as a computer, comprises a housing having a plurality ofwalls, a door provided on a wall of said housing, said door having anopen position and a closed position, a connection socket provided on aninterior portion of said housing, and an insertion mechanism mounted onsaid door. The insertion mechanism comprises a driver portion accessiblefrom an exterior side of said door and movable from an unlatchedposition to a latched position, and a movable mount provided on aninterior side of said door and mechanically coupled to said driverportion. A circuit board assembly is mounted on said movable mount andhas an edge connector along a forward edge of said circuit boardassembly such that when said driver portion moves from said unlatchedposition to said latched position, said movable mount moves in a forwarddirection, inserting said edge connector into said connection socket.

In accordance with another aspect of the present invention, a method formounting a circuit board assembly with an edge connector is described.The method comprises providing a housing having an open door on one sideand a connection socket therein, providing a movable mount on aninterior side of said door, mounting a circuit board assembly onto saidmovable mount, closing said door, and actuating a driver from anexterior side of said door, said driver moving said movable mount in aforward direction to mate said edge connector with said connectionsocket.

In accordance with yet another aspect of the present invention, aelectronic system comprises a housing, a rail system provided on saidhousing, and a driver portion. The driver portion comprises a handlehaving a unlatched position and a latched position, and a latch driverconnected to said handle and rotatably connected to said housing througha first axis of rotation. A mount is slideably attached to said railsystem and engages said latch driver such that as said handle is movedfrom said unlatched position to said latched position, said latch driverexerts a force on said mount in a forward direction urging said mountfrom a first location along said rail system to a second location alongsaid rail system. A connection socket is provided on said housing, and acircuit board assembly is provided having an edge connector along aforward edge, said circuit board assembly being attached to said mountsuch that when said mount is in said first location, said edge connectoris distant from said connection socket, and when said mount is in saidsecond location, said edge connector is mated with said connectionsocket.

Other features and advantages of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings which illustrate, by way of example, the featuresin accordance with the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be better understood, and its numerousobjects, features, and advantages made apparent to those skilled in theart by referencing the accompanying drawings.

FIG. 1 is an isometric view of a computer system in accordance with anembodiment of the present invention.

FIGS. 2a-2 b are isometric views of the computer system with the housingdoor in the closed position.

FIG. 3 is an isometric view of the computer system with the housing doorremoved.

FIGS. 4a-4 b are isometric views of the interior and exterior sides ofthe housing door.

FIGS. 5a-5 b are isometric views of the interior and exterior sides of acircuit board assembly.

FIGS. 6a-6 b are isometric views of the exterior and interior sides of aboard tray.

FIG. 7a is an isometric view of the exterior side of a movable mount.

FIG. 7b is a plan view of the interior side of the movable mount.

FIG. 7c is a bottom view of the movable mount.

FIGS. 8a-8 b are plan views of an interior side of a door.

FIG. 9 illustrates the movement of a boss on a latch driver.

FIGS. 10a-10 b are side views of the movement of a circuit boardassembly.

The use of the same reference symbols in different drawings indicatessimilar or identical items.

DETAILED DESCRIPTION

FIG. 1 shows a computer system 100 having a circuit board assembly 101in accordance with an embodiment of the present invention. Computersystem 100 includes a housing 102 which encloses all of the componentsof the system. On a side of housing 102 is a door 104, shown in FIG. 1in the open position. With door 104 in the open position, the internalcomponents of computer system 100 can be easily accessed. To improveclarity, much of the detail of the interior of housing 102 is not shown.It will be understood that housing 102 includes various computercomponents, such as power supplies, a mid-plane circuit board forproviding input/output (I/O) connections, and peripheral cards.

Circuit board assembly 101 is mounted on an interior side of the door104 via a movable mount 160 (not shown in FIG. 1 ). Circuit boardassembly 101 includes a board tray 142 and a circuit board 110 used as abase board for processor bays 112 and memory modules 114. Edgeconnectors 111 are formed along a forward edge of circuit board 110. Inthe embodiment shown, edge connectors 111 comprise one NLX-type 340 pin,1 mm pitch edge connector 111 a, one NLX-type 192 pin edge connector 111b, and one 50 pin, 2.54 mm pitch, standard edge connector 111 c.Processor bay 112 can receive up to six microprocessors 116, and eightmemory modules 114 may be, for example, SDRAM or other types of RAMmemory. In the embodiment shown in FIG. 1, circuit board assembly 101weighs approximately 30 pounds. Because of the significant weight ofcircuit board assembly 101, a hydraulic lift 108 is provided to allowdoor 104 to be opened and closed smoothly and to prevent door 104 fromslamming shut. System cooling fans 106 are positioned so that theydirect a cooling air flow across microprocessors 116, memory modules114, and other computer components when door 104 is in the closedposition. A set of processor cooling fans 107 may also be provided foradditional cooling of processors 116.

As shown in FIG. 2a, with door 104 of computer system 100 in the closedposition, circuit board assembly 101 and the interior of housing 102 areno longer accessible. Handle 120 provided in a recess 118 on an exteriorside of door 104 is used to mate edge connector 111 a, 111 b, 111 c ofcircuit board 110 with connection sockets 124 a, 124 b, 124 c (shown inFIG. 3), as will be described below. FIG. 2a shows handle 120 in theunlatched position, and FIG. 2b shows handle 120 in the latchedposition. Handle 120 may be made of glass-filled polycarbonate, which isadvantageously lightweight, strong, and is easily manufactured.

FIG. 3 shows an isometric view of computer system 100 with door 104removed to improve clarity. Door 104 is pivotally mounted through frontand rear pivot brackets 141 onto joint members 122, which are providedon an interior of housing 102. Shoulder bolts through pivot brackets 141(FIG. 4b) and joint members 122 securely connect door 104 to housing102, and act as axles about which door 104 pivots. Connection sockets124 are provided in the interior of housing 102 at a location such thatwhen door 104 is in the closed position, edge connectors 111 a, 111 b,111 c of circuit board 110 are adjacent connection sockets 124 a, 124 b,124 c, respectively. In the embodiment shown, a clearance of 15.5 mm isprovided between edge connectors 111 and connection sockets 124 a, 124b, 124 c so that door 104 can be moved between the opened and closedpositions without edge connectors 111 and connection sockets 124 a, 124b, 124 c contacting each other. Connection sockets 124 a, 124 b, 124 cconnect the components of circuit board assembly 101 with a mid-planeboard 190.

The exterior and interior sides of door 104 with circuit board assembly101 removed are shown in FIGS. 4a and 4 b, respectively. Latch driver126 is rotatably mounted to the interior side of door 104 through firstpivot point bolt 128, and engages latch follower 132 through gears 130a, 130 b. Latch follower 132 is rotatably mounted to door 104 throughsecond pivot point bolt 134. Interior handle portion 121 is provided onthe interior side of door 104 to provide handle 120 with increasedstrength and integrity. First and second bosses 136 and 137 protrudefrom latch follower 132 and latch driver 126, respectively. Inner doorrails 138 and outer door rails 140 are also provided on the interiorside of door 104. Latch driver 126, latch follower 132, bosses 136 and137, handle 120, and interior handle portion 121 comprise the driverportion of the computer system 100.

FIGS. 5a and 5 b, respectively, show exterior and interior sides ofcircuit board assembly 101. Circuit board assembly 101 includes a boardtray 142 having a set of inner tray rails 144 and a set of outer trayrails 146. The exterior and interior sides of board tray 142 are shownin FIGS. 6a and 6 b, respectively. Circuit board assembly 101 alsoincludes circuit board 110 and all of its mounted components. Whencircuit board assembly 101 is mounted on door 104, outer tray rails 146on the exterior side of board tray 142 loosely mate with outer doorrails 140 on the interior side of door 104, and inner tray rails 144loosely mate with inner door rails 138, thereby allowing circuit boardassembly 101 to linearly slide relative to door 104. Two locator pins148 protrude from a shoulder 150 of board tray 142 in a forwarddirection. As used herein, forward is determined by the orientation ofcircuit board 110 and is defined as the direction in which circuit board110 is moved to insert edge connectors 111 into their correspondingconnection sockets 124.

FIGS. 7a, 7 b, and 7 c show isometric, plan, and top views,respectively, of movable mount 160 in accordance with one embodiment ofthe present invention. FIG. 7a shows the exterior side of mount 160,i.e., the side shown is adjacent to door 104 during operation. Movablemount 160 includes a first slot 164 and a second slot 166. Outer edges162 on movable mount 160 loosely engage the inner portion of inner doorrails 138 on the interior side of door 104, and allow movable mount 160to slide forward and rearward relative to door 104. Flanges 172 providedat the top of movable mount 160 include holes 174 through whichthumbscrews 152 (FIGS. 6a-6 b) pass when board tray 142 is attached tomovable mount 160. First center slot 168 and second center slot 170provide clearance for pivot point bolts 134 and 128, allowing movablemount 160 to be more closely mounted to latch driver 126 and latchfollower 132 on door 104. Tabs 176 provided at the bottom of mount 160fit into notches 154 of board tray 142, thereby providing additionalsupport for tray 142.

FIG. 8a shows in greater detail an interior side of door 104 with handle120 in the unlatched position. The orientation of interior handleportion 121 provided on the interior side of door 104 corresponds to theorientation of handle 120, which is provided on the exterior side ofdoor 104. An outline of movable mount 160 is shown using phantom lines.FIG. 8b shows the interior side of door 104 with handle 120 in thelatched position.

The operation of this embodiment of the present invention is as follows.Movable mount 160 is attached to the interior side of door 104 byloosely engaging edges 162 on mount 160 with inner door rails 138 ondoor 104. Bosses 136 and 137 are received into slots 164 and 166,respectively. Edges 162 loosely engage inner door rails 138 to provide“float,” wherein movable mount 160 is linearly guided by edges 162 andinner door rails 138 in forward and backward directions, but is capableof limited lateral movement.

Circuit board assembly 101 is attached to door 104 by slideably engagingouter tray rails 146 on board tray 142 with outer door rails 140 on door104 and inner tray rails 144 with inner door rails 138. When circuitboard assembly 101 is properly mounted, flanges 172 on movable mount 160abut shoulder 150 on tray 142. The engagement between outer tray rails146 and outer door rails 140 and between inner tray rails 144 and innerdoor rails 138 include additional clearance to allow “float” betweenboard tray 142 and door 104. Thumbscrews 152 in board tray 142 securelyattach to threaded fasteners 174 in movable mount 160, preventingrelative movement between the two components. Tabs 176 at the bottom ofmovable mount 160 are received in notches 154 to provide additionalsupport for circuit board assembly 101.

With circuit board assembly 101 in place, door 104 is closed. The drivermechanism enables blind mating, in which edge connectors 111 of circuitboard 110 are mated with connection sockets 124 after door 104 is closedand circuit board 110 is no longer directly accessible by the user. Whendoor 104 is closed, edge connectors 111 are aligned adjacent toconnection sockets 124, but are separated by a distance of approximately15.5 mm. This separation allows door 104 to be closed without edgeconnectors 111 grazing or otherwise making undesirable contact withconnection sockets 124.

When handle 120 is in the unlatched position, as shown in FIG. 8a,movable mount 160 is in a rearward position such that pivot point bolts128 and 134, which form the axes of rotation for latch driver 126 andlatch follower 132, are located at the first forward end of slot 168 andsecond forward end of slot and 170 of movable mount 160, and first boss136 and second boss and 137 are located at the inner ends of slots 164and 166. As handle 120 is rotated into the latched position, latchdriver 126 rotates in a clockwise direction, moving second boss 137 in aclockwise direction.

The path traced by second boss 137 as handle 120 is rotated is shown inFIG. 9. The x-direction corresponds to the forward direction, as definedby the orientation of the edge connectors 111 on circuit board 110.Circle 180 shows the radial location of second boss 137 relative tofirst pivot point bolt 128. Locations 182, 184, and 186 indicatepositions of second boss 137 as handle 120 rotates. Location 184 definesa rotational position of 0°, location 182 defines a rotational positionof θ greater than 0° and less than 180°, and location 186 defines arotational position of φ less than 0°.

In the embodiment shown in FIG. 9, when handle 120 is in the unlatchedposition, second boss 137 is at first location 182, which corresponds toa rotational position of approximately 45°. As handle 120 is rotatedfrom the unlatched position to the latched position shown in FIG. 8b,second boss 137 travels in a clockwise direction along the path tracedby circle 180 until it reaches location 184, which is the forwardmostposition along second boss 137's path. At this point, second boss 137has traveled forward a linear distance a in the x-direction. The shapeof slot 166 in movable mount 160 allows free movement of second boss 137in the y-direction, but any movement of boss in the x-direction forcessecond boss 137 to abut the inner edge of slot 137. Thus, the forwardmovement of second boss 137 imparts a forward movement onto movablemount 160 through slot 166, thereby moving movable mount 160 and circuitboard assembly 101 forward a distance a. Distance a is selected suchthat edge connectors 111 in circuit board 110 move forward sufficientlyfar such that connectors 111 are fully inserted into connection sockets124.

Side views of circuit board assembly 101 as handle 120 is moved into thelatched position are illustrated in FIGS. 10a and 10 b. FIG. 10a showsboard assembly 101 with handle 120 in the unlatched position, such thatedge connectors 111 are separated from connection sockets 124. Whencircuit board assembly 101 is moved forward a distance a by the drivermechanism, edge connectors 111 are fully inserted into connectionsockets 124.

Latch follower 132 helps the driver mechanism to provide a morebalanced, controlled force onto movable mount 160. Gears 130 a on latchdriver 126 engage gears 130 b on latch follower 132 such that theclockwise rotation of latch driver 126 imparts a counter-clockwiserotation of latch follower 132. As handle 120 is moved from theunlatched position to the latched position, first boss 136 on latchfollower 132 imparts a force onto slot 164 in a similar way as describedabove with respect to second boss 137. Providing two equal forces ontomovable mount 160 results in a more balanced insertion of edgeconnectors 111.

Edges 162 on mount 160 and outer tray rails 146 on board tray 142 areused to help guide the movement of movable mount 160 in the x-direction.Because of the number of moving parts, manufacturing tolerances, andflexibility of various members in the computer system 100, as movablemount 160 slides forward, edge connectors 111 and connection sockets 124may not be perfectly aligned. As described above, outer tray rails 146loosely mate with outer door rails 140 to provide circuit board assembly101 with “float,” which accommodates for imprecision in the alignment ofedge connectors 111 and connection sockets 124. Similarly, edges 162 areprovided with “float” in their engagement with inner door rails 138. The“float” allows circuit board 110 to be slightly shifted laterally whenbeing mated with connection sockets 124.

Locator pins 148 are used as alignment inserts to guide circuit boardassembly 101 as it is being pushed into place by the driver mechanism.As handle 120 begins to move to the latched position but before edgeconnectors 111 mate with connection sockets 124, locator pins 148 meetlocator pin holes 192 in housing 102. Locator pin holes 192 serve asalignment receivers and may be formed in a funnel-like shape such thatif locator pins 148 are slightly off-center, they are guided to theproper position as circuit board assembly 101 continues moving forward.Accordingly, the “float” provided by the railing system allows theentire circuit board assembly 101 to be shifted laterally by the matingof pins 148 with holes 192 in order to obtain the proper alignment. Doorguide pins 194 protrude upwards from housing 102 and mate with doorguide pin holes 196 on door 104. Door guide pins 194 and holes 196 serveto further align edge connectors 111 with connection sockets 124.

In an alternative embodiment, edges 162 and outer tray rails 146precisely engage inner door rails 138 and outer door rails 140 on door104 such that no float is provided. In such an arrangement, thealignment and tolerances of the elements in computer system 100 involvedwith the mating of circuit board assembly 101 are tightly controlled toensure repeatable connections and disconnections of edge connectors 111.

The embodiment shown in FIGS. 8a-8 b include an overtravel mechanism toprevent inadvertent disconnection of edge connectors 111 from connectionsockets 124 in the event of a mechanical shock to system 100. As handle120 is moved into the latched position, latch driver 126 rotates suchthat second boss 137 moves beyond the uppermost location 184. Whenhandle 120 reaches the fully latched position, second boss 137 comes torest at third location 186. At this point, second boss 137 has moved toa rotational position φ of approximately −5°, which corresponds to alinear distance b in a rearward direction. Distance b is sufficientlysmall that, despite the slight rearward movement of circuit board 110imparted by the overtravel of second boss 137, edge connectors 111retain a secure and complete contact with connection sockets 124. Oncesecond boss 137 has reached location 186, it is prevented from travelingany further in the clockwise direction because second boss 137 abuts theend of slot 166.

Any force applied to circuit board assembly 101 in the rearwarddirection would be passed onto second boss 137 through movable mount160. With handle 120 in the overtravel position, a rearward forceapplied to second boss 137 would tend to force latch driver 126 torotate in the clockwise direction. Because latch driver 126 is preventedfrom any further rotation in that direction, circuit board assembly 101is essentially locked in place until latch driver 126 is rotated in acounter-clockwise direction to move second boss 137 beyond theforwardmost location 184. Latch follower 132 and second boss 136 providea similar overtravel protection as described above.

In order to open door 104, the above-described process of mating circuitboard assembly 101 is reversed. Handle 120 on the exterior of door 104is rotated from the latched to the unlatched position, which causessecond boss 137 to rotate from location 186 to location 182. As bossmoves in the x-direction, it presses against a rearward edge of slot166, thereby moving movable mount 160 in the rearward direction andwithdrawing edge connectors 111 from connection sockets 124. Once edgeconnectors 111 are fully withdrawn, door 104 can be safely openedwithout damaging circuit board assembly 101.

Manual door latches 188 can be used to lock door 104 in place whencomputer system 100 is in use. Solenoid latch 198 provides an additionalprotection against inadvertent disconnection of the edge connector 111.Latch 198 is electronically coupled to the power supply in computersystem 100 such that when computer system 100 is receiving power and isin use, latch 198 closes. With latch 198 closed, handle 120 is locked inplace, preventing any rotation. After the power to system 100 is shutoff, solenoid latch 198 opens, allowing handle 120 to be rotated to theunlatched position.

As can be seen from the figures, the above-described embodiment of thepresent invention enables blind mating of a circuit board with the edgeconnectors using an insertion mechanism which resides adjacent to thebottom surface of the board. This design is less intrusive than earlierapproaches, and provides simple, unobstructed access to the interior ofthe computer system. In another embodiment of the present invention, thedriver mechanism and circuit board assembly are not be mounted onto adoor in the housing, but instead are contained elsewhere within thehousing.

Although the invention has been described with reference to particularembodiments, the description is only an example of the invention'sapplication and should not be taken as a limitation. In particular, eventhough in the description above circuit board 110 is mounted such thatedge connector 111 is oriented along an edge of door 104 farthest fromthe side about which door 104 rotates, in alternative embodiments,circuit board 110 can be mounted in any orientation. In anotherembodiment, circuit board assembly 101 comprises a circuit board alone,and is mounted directly to movable mount 160 without the use of boardtray 143. Further, although the embodiments described above refer to acomputer system, the electronic system in accordance with the presentinvention need not be limited to a computer. Various other adaptationsand combinations of features of the embodiments disclosed are within thescope of the invention as defined by the following claims.

We claim:
 1. A computing system comprising: a case, the case including adoor; and, electronic circuitry housed within the case, the electroniccircuitry comprising: a first circuit board mounted on the door, thefirst circuit board having a first connector, and additional circuitrymounted within the case, the additional circuitry having a secondconnector that is mechanically and electrically connectable to the firstconnector; wherein when the door is in an open position the firstconnector is mechanically and electrically disconnected from the secondconnector; and, wherein when the door is in a closed position the firstconnector is mechanically and electrically connectable to the secondconnector.
 2. A computing system as in claim 1 wherein the firstconnector is an edge connector and wherein the second connector is aconnection socket configured to receive the edge connector.
 3. Acomputing system as in claim 1 wherein the first circuit board ismounted on the door by a movable mounting device, the movable mountbeing able to move the first circuit board back and forth when the dooris in the closed position, so that: when the door is in the closedposition and the movable mount moves the circuit board into an engagedposition, the first connector is mechanically and electrically connectedto the second connector; and, when the door is in the closed positionand the movable mount moves the circuit board into a disengagedposition, the first connector is mechanically and electricallydisconnected from the second connector.
 4. A computing system as inclaim 1 wherein the movable mounting device includes a handle accessibleto a user when the door is in the closed position, the handle allowingthe user to control the movable mount to move the circuit board back andforth from the engaged position to the disengaged position.
 5. Acomputing system as in claim 1 wherein the first circuit board serves asa base board for processor bays and memory modules.
 6. A computingsystem as in claim 1 wherein the additional circuitry includes a powersupply, a mid-plane circuit board for providing input/outputconnections.
 7. A computing system as in claim 1 wherein pivot bracketsattached to the door allow the door to swing to the open position and tothe closed position.
 8. A method for facilitating access to electroniccircuitry housed in a case, comprising the following steps: (a) mountinga first circuit board on a door of the case, the first circuit boardhaving a first connector, and (b) mounting additional circuitry withinthe case, the additional circuitry having a second connector that ismechanically and electrically connectable to the first connector; and,(c) aligning the first and the second connector so that when the door isin an open position the first connector is mechanically and electricallydisconnected from the second connector, and when the door is in a closedposition the first connector is mechanically and electricallyconnectable to the second connector.
 9. A method as in claim 8 whereinin step (a) the first connector is an edge connector and wherein in step(b) the second connector is a connection socket configured to receivethe edge connector.
 10. A method as in claim 8 wherein step (a) includesthe following substep: (a.1) mounting the first circuit board using amovable mounting device, the movable mount being able to move the firstcircuit board back and forth when the door is in the closed position, sothat when the door is in the closed position and the movable mount movesthe circuit board into an engaged position, the first connector ismechanically and electrically connected to the second connector, and,when the door is in the closed position and the movable mount moves thecircuit board into a disengaged position, the first connector ismechanically and electrically disconnected from the second connector.11. A method as in claim 10 wherein substep (a.1) comprises including ahandle in the movable mounting device, the handle being accessible to auser when the door is in the closed position, the handle allowing theuser to control the movable mount to move the circuit board back andforth from the engaged position to the disengaged position.
 12. A methodas in claim 8 wherein in step (a) the first circuit board serves as abase board for processor bays and memory modules.
 13. A method as inclaim 8 wherein in step (b) the additional circuitry includes a powersupply, a mid-plane circuit board for providing input/outputconnections.
 14. A method as in claim 8 additionally comprising thefollowing step: attaching pivot brackets to the door to allow the doorto swing to the open position and to the closed position.
 15. Housingfor electronic circuitry comprising: a door onto which a first circuitboard is mounted, the first circuit board having a first connector; and,an enclosure to which the door is attached, additional circuitry beingmounted within the enclosure, the additional circuitry having a secondconnector that is mechanically and electrically connectable to the firstconnector; wherein when the door is in an open position the firstconnector is mechanically and electrically disconnected from the secondconnector; and, wherein when the door is in a closed position the firstconnector is mechanically and electrically connectable to the secondconnector.
 16. Housing as in claim 15 wherein the first connector is anedge connector and wherein the second connector is a connection socketconfigured to receive the edge connector.
 17. Housing as in claim 15wherein the first circuit board is mounted on the door by a movablemounting device, the movable mount being able to move the first circuitboard back and forth when the door is in the closed position, so that:when the door is in the closed position and the movable mount moves thecircuit board into an engaged position, the first connector ismechanically and electrically connected to the second connector; and,when the door is in the closed position and the movable mount moves thecircuit board into a disengaged position, the first connector ismechanically and electrically disconnected from the second connector.18. Housing as in claim 17 wherein the movable mounting device includesa handle accessible to a user when the door is in the closed position,the handle allowing the user to control the movable mount to move thecircuit board back and forth from the engaged position to the disengagedposition.
 19. Housing as in claim 15 wherein the first circuit boardserves as a base board for processor bays and memory modules. 20.Housing as in claim 15 wherein the additional circuitry includes a powersupply, a mid-plane circuit board for providing input/outputconnections.